applying the latest version of the national ventilation ... · located on cape cod, massachusetts;...

Applying the latest version of the National Ventilation Standard

Heyoka Solutions, LLC

Paul H. Raymer

All Contents Copyright 2013 by Heyoka Solutions, LLC. ALL RIGHTS RESERVED. Any use of materials, photographs, drawings, depictions or content, including reproduction, modification, distribution or republication, without the prior written consent of Heyoka Solutions, LLC, is strictly prohibited. Copyright infringement is a violation of federal law subject to criminal and civil penalties.

©Heyoka Solutions, LLC 2013

Located on Cape Cod, Massachusetts;

Member ASHRAE 62.2 SSPC 10+ years

HERS Rater, BPI Analyst, Envelope, Heating, and AC/Heat Pump Certified;

Certified IREC/ANSI Assessor;

Author of the Residential Ventilation Handbook


One cubic foot of air (cfm) moves into a house only if one

cubic foot of air moves out of the house.

1cfm in = 1 cfm out


Air always flows from areas of higher pressure to

areas of lower pressure.

(Second Law of Thermodynamics)


• CFM – cubic feet per minute;

• FPM – feet per minute

• Static pressure – resistance to flow - measured in "WC (iwg) or Pa (Pascal);

• Sone – linear measurement of sound;

• HVI (Home Ventilating Institute) and HRAI (Heating Refrigeration and Air Conditioning Institute of Canada).


Whole Building Ventilation is dilution ventilation – “the solution to pollution is dilution”.

Courtesy of Panasonic

& Paddy Morrissey


(4) “Air” Changes = 6.25% Pollution

Pure “Pollution” (2) “Air” Changes 25% pollution

(1) “Air” Change

50% pollution

(3) “Air” Changes

12.5% pollution


1. Natural airflow through the building depends on many factors including temperatures, wind, mechanical forces, etc. It is not constant. It is variable.

2. People essentially need the same amount of fresh air to breathe. It is constant. It is not variable.

3. You cannot satisfy a constant need with a variable source unless that source constantly exceeds the need.

9


10

People

Building Air Leakage

Time

Wea

ther

Over ventilated

Under ventilated


National Ventilation Standard

Single family, multifamily up to three stories, and manufactured and modular buildings;

Considers chemical, physical, and biological contaminants but does not consider thermal comfort;

Acceptable IAQ will not necessarily be achieved even if all requirements are met.


Requires whole-building ventilation in all new and the majority of existing homes;

Provides sizing procedures;

Outlines equipment parameters;

Requires installed system testing.

Requires local exhaust ventilation in bathrooms and kitchens in all homes;

Provides sizing procedures;

Outlines equipment parameters;

Requires installed system testing.


Select a whole building airflow from the table (or calculate it);

Select appropriate airflow rates for local exhaust;

Select quiet equipment whose performance is certified by HVI;

Install it so it works; Test it to prove that it works; Document the design.

Edward Brannock, Pilot & Entrepreneur


Ventilation rate by the formula or by the table.

Pick a number from the table:

How big is the house?

How many bedrooms does it have?


Floor Area (ft2) 1 2 3 4 5

<500 ft2 30 38 45 53 60

501 – 1000 45 53 60 68 75

1001 - 1500 60 68 75 83 90

1501 - 2000 75 83 90 98 105

2001 - 2500 90 98 105 113 120

2501 - 3000 105 113 120 128 135

3001 - 3500 120 128 135 143 150

3501 - 4000 135 143 150 158 165

4001 - 4501 150 158 165 173 180

4501 - 5000 165 173 180 188 195

Example: 1200 square foot house with 2 bedrooms. Requires 68 cfm continuous ventilation.


Formula:

Qtot = 0.03Afloor + 7.5 x (Nbedrooms +1)

Example: Same 1200 square foot 2 bedroom house: (1200 x .03) + 7.5 x (2 + 1) = 36 + 22.5 = 58.5 cfm Lower airflow than the table, but remember that 62.2 is a MINIMUM ventilation guideline.


If the home has had a blower door test, the actual infiltration can be used to adjust the ventilation rate.

0.052* x CFM50 x S x wsf = “infiltration credit” (Qinf)

* Derivation of the 0.052 constant: ELA = (Q50/50.65) x (dP.65)x sqrt(rho/2 x dP)) NL = 1000 x ELA/Afloor x S Qinf(cfm) = (NL x wsf x Afloor)/7.3 dP = delta P (4) Rho = density of air (1.2 kg/m3)


Atlantic City Intl AP 0.53

Belmar Asc 0.52

Caldwell/Essex Co. 0.44

Cape May Co 0.49

McGuire AFB 0.48

Millville Muni AP 0.44

Newark Intl AP 0.54

Teterboro AP 0.5

Trenton Mercer County AP 0.48

There are 1100 ‘wsf’ factors!

1 Story 1

1.5 Stories 1.18

2 Stories 1.32

2.5 Stories 1.44

3 Stories 1.55

Building height

factors (s)

Wsf factors for NJ:


1200 square foot, 2 bedroom, 1 story house in Trenton, NJ

Initial Blower Door number of 1400 CFM50

0.052 x CFM50 x S x wsf = “infiltration credit”

0.052 x 1400 x 1 x 0.48 = 34.9




Original whole building ventilation rate = 58.5

With infiltration credit:

58.5 – 34.9 cfm = 24 cfm




Final Blower Door number of 1100 CFM50

0.052 x CFM50 x S x wsf = “infiltration credit”

0.052 x 1100 x 1 x 0.48 = 27.5




Final Blower Door number of 1100 CFM50

Original whole building ventilation rate = 58.5

With infiltration credit:

58.5 – 27.5 cfm = 31 cfm



Blower door value

Qinf (Infiltration credit)

Whole building ventilation rate

1400 CFM50 34.9 cfm 24 cfm

1100 CFM50 27.5 cfm 31 cfm


Gives credit for existing fans and operable windows and infiltration.


Compliance options for existing buildings:

o Whole building ventilation rate is the sum of the whole building rate determined by table 4.1 plus any deficit for existing spot ventilation fans minus an infiltration credit.

Measure the airflow through existing fans and compare that to the local exhaust requirements;

An operable window reduces the deficit by 20 cfm.


1580 square foot, 3 bedroom, 1 story house in Madison, WI (wsf = 0.61)


Kitchen has a window and a fan that moves 60 cfm.

Bathroom has a window and a fan that moves 20 cfm. Existing fans can be left in place.

Whole building ventilation rate can be increased.


Operable Window = 20 cfm Kitchen requires 100 cfm. It has a window and a 60 cfm fan: 100 – 60 – 20 = 20 cfm “deficit” Bathroom requires 50 cfm. It has a window and a 20 cfm fan: 50 – 20 – 20 = 10 cfm “deficit” Ventilation deficit = (20 + 10)/4 = 7.5 Original Whole Building Ventilation rate:

1580 x 0.03 + 7.5 x (3 + 1) = 77 cfm Adjusted Whole Building Ventilation rate = 77 + 7.5 = 85 cfm


Adjusted Whole Building Ventilation rate = 77 + 7.5 = 85 cfm With Infiltration Credit for original Blower door number (1400 CFM50) :

0.052 x 1400 x 1 x 0.61 = 44.4

77 + 7.5 - 44 = 41 cfm (whole building ventilation rate) With tightened home Infiltration Credit:

0.052 x 1100 x 1 x 0.61 = 34.9

77 + 7.5 – 34.9 = 50 cfm

(whole building ventilation rate)


1580 square foot, 3 bedroom, 1 story house in Madison, WI

Start

Blower door 1400 CFM50

Tightened Blower door 1100 CFM50

Initial Flow Rate 77 cfm

With Appendix A only

85 cfm

With Infiltration Credit & Appendix A

41 cfm 50 cfm


• The existing building calculation can only be

used for existing homes.

• A really leaky existing house can have a required whole building mechanical ventilation rate of 0 cfm.


The intermittent operation option adds a bit of complexity.

Short durations (3 hours or less cycle time) are simple:

Run ½ the time double the required flow;

Run 1/3 the time triple the flow.


Pin Timer

Electronic Timer

Programmable Intermittent Timer

Fan & Light Switch


Select equipment with performance certified by AMCA or HVI;

Very quiet: 1 sone or less – quieter than a quiet refrigerator!

Exhaust or Supply only ventilation;

Mechanically balanced ventilation;

Mechanically balanced ventilation with heat or energy recovery.


Desiccant wheel ERV 2nd Law of Thermodynamics – Heat moves to cold, wet moves to dry Heat Recovery Ventilator (HRV) transfers heat from the warm air stream to the cool air stream. Energy Recovery Ventilator (ERV) transfers heat and moisture from warm, moist air stream to the cooler, drier air stream.


If the house is tight, in a heating dominated climate, less moisture inside the house will be removed by an ERV because it will be transferred to the incoming air stream. HRV and ERV efficiency ratings are based on balanced operation. Their efficiencies will change if they are connected to air handlers and run in an unbalanced condition. They need to be installed where their filters and cores can be maintained. They do not supply EXTRA air to balance other devices.


Fresh air supply

with a motorized

damper

Fan cycler switch runs air handle at 20

minute intervals

Supply side of air handler

Kitchen Bedroom

Bath

Source: Paul Francisco


Outside air supplied to return side of the air handler

Aldes CAR

AirCycler Field Controls Damper


Local ventilation removes the pollutants at the source.


Intermittent Continuous

Kitchen 100 cfm Vented range hood required if

exhaust fan flow rate is less than 5 kitchen ACH

5 ACH

Bathroom 50 cfm 20 cfm


Typical ceiling insert

bath fans.

Certified by HVI or AMCA

for both airflow and sound.

http://www.bobvila.com/SmartBuys/110_CFM_1_3_Sones_Energy_Star_Fan_Fluorescent_Light_Night_Li-p481551.html


Range hoods

Exterior mounted fan


Select a whole building airflow from the table (or calculate it);

Select appropriate airflow rates for local exhaust;

Select quiet equipment whose performance is certified by HVI;


Air is lazy;

Electrons are more forgiving;

Never use “duck” tape;

Always choose the shortest, straightest path to the outside;

System must be serviceable;

Never, never, never vent into the attic.


• In-line fans are designed to drag air

through ducts;

• Propeller or axial fans are not good for

ducts;

• Backdraft dampers can cut the airflow in

half.



The effects of duct length on airflow performance in more detail.

Actual length is the actual, physical

length of the duct run (how far is it from

A to B);

Equivalent length is equivalent

resistance to the airflow generated by

the fittings;

Effective length is the sum of the Actual

and Equivalent lengths.

Actual length + Equivalent length = Effective length



Description Equivalent Length

(Ft) for rigid

ducting

45° adjustable

elbow, 2-piece

5

90° adjustable

elbow, 4-piece

10

Wye, equal sizes 10

Tee, take-off 50

Tapered

increaser/reducer

4

Hard

increaser/reducer

8

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Description Equivalent Length

(Ft)

Triangular wall cap for round duct

with backdraft damper & bird screen

28

Triangular wall cap for round duct

with bird screen, without backdraft

damper

14

Rounded wall cap for round duct


14

Louvered wall cap 16

Low profile soffit vent with

backdraft damper and bird screen

33

Roof cap, low-profile for round duct


60

Roof cap, ‘goose-neck’, for round

duct with backdraft damper & bird

screen

71

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Increasing the duct diameter from 4” to 6” will dramatically reduce the friction loss.

From Jennings, Environmental Engineering Analysis and Practice ,1970

7.5 Pa 62.5 Pa


Ducts need to be supported;

Choose the shortest path;

Ducts running through unheated

spaces must be insulated.


“In theory, everything works in practice. In practice, it’s different.”

Yogi Berra


Duct Blaster with DG700

Q200 Duc-Tester

with DM-2 gauge

http://www.retrotec.com/products/gauges/dm2_series_2_channel_digital_p/1.jpg


Calibrated Duct Tester Fan Under Test

Point A

When the pressure at Point A = 0 pa, the flow through the Duct Tester fan = the flow through the fan under test.


1. Set the Device on the DG700 to EXH;

2. Set the Config to correspond to the opening on the Exhaust hood (A1, B2, C3);

3. “T” both channel inputs to the hose connected to the Exhaust hood;

4. If the pressure on Channel A exceeds 8 pa, open the Exhaust hood to the next notch;

5. Read the flow on Channel B.

If the flow exceeds 124 cfm, a different device must be used.


A Balometer will measure flows between 10 and 500

cfm.

Vane anemometer is less effected by ambient conditions like temperature, humidity and altitude. Accurate between 0 and 75 cfm.


Brand Model ID Required Airflow

Tot. Installed Airflow Normal Boost

Fanwho Quantum 3 36.5 42 76

Ventilation Product Information:

Brand Model ID Function (Multi-speed, intermittent, etc.)

Fanwho IAQ4040 Multi-function, variable flow

Control:

System Function & Operating Notes

HRV designed to exhaust air from the bathrooms and supply air to the bedrooms, low speed continuous operation, manual boost.

Req. Maintenance Clean filters monthly. Replace annually.

Clean the core annually.


Thanks for listening

Paul Raymer

[email protected]

www.HeyokaSolutions.com

. . . and that’s the name of that tune!

Read the book. Don’t wait for the movie!

mailto:[email protected]

applying the latest version of the national ventilation ... · located on cape cod, massachusetts;...

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